More
legacy questions - with some mark schemes

1The isotope of 238 92 U is at the head of a chain
of radioactive decays. The first few decays in the series are shown below.

(a)Use
data from the data book to identify the decay process X and the decay products
Y and Z.

(3)

(b)(i) Calculate the
mass difference between U-238 andTh-234.

(ii) Show that the energy released in this decay is about 4
MeV.

(4)=(7)

3

A trolley of mass 0.40 kg is attached to two fixed points by springs as
shown. When it is displaced horizontally 0.20 m from its equilibrium position
and released, it moves with simple harmonic motion with a period of 4.0 s.

(a)Ignoring any frictional effects, calculate

(i) the maximum
speed of the trolley,

(ii) the maximum
kinetic energy of the trolley,

(iii)the effective
stiffness constant, k, of the spring system.

(5)

(b)In practice, frictional forces gradually reduce the kinetic energy of
the trolley. If the trolley loses one-tenth of its kinetic energy in every
complete oscillation, calculate the kinetic energy of the trolley at the
equilibrium position when it has made four complete oscillations. Assume that
the kinetic energy when it first passes the equilibrium position is the value
which you have calculated in (a) (ii).

(2)=(7)

4 (a) Explain the meanings of the following terms:

free vibration

forced vibration

resonance

(3)

(b)

A, B and C are three pendulums, each with a light paper cone for a bob.
X is another pendulum with a heavy metal bob. Pendulum X is displaced
perpendicular to the plane containing the bobs at rest and then released.

Compare the motions of pendulums A, B and C to that of X, with
reference to period and amplitude.

Pendulum A:

Pendulum B:

Pendulum C

(3)=(6)

5(a)
Explain what is
meant by

(i) unpolarised light

(ii) plane polarised light

(2)

(b)

A light source appears bright when viewed through two pieces of
polaroid, as shown. Describe what is seen when B is slowly rotated through 180o
in its own plane.

(2)

(c)(i)Tick which of the following categories of waves can be polarised.

(ii) State your criterion for deciding which to
tick.

.(2)=(6)

6 (a) Describe, with the aid of a diagram, how you would set up the apparatus
to produce and observe optical interference fringes using a double slit and
any other essential apparatus.

(3)

(b)A student set up a two-slit interference experiment in the laboratory
to determine the wavelength of the yellow light from a sodium lamp. A
travelling microscope was used to make measurements on the fringes produced
and the readings obtained are shown below. The slit separation was 0.40 mm and
the distance from the double slit to the plane in which the fringes were
viewed was 1.80 m.

Use these values to calculate the wavelength of the yellow light.

(4)

(c)For the apparatus used in (b), describe and explain the effect on the
appearance of the fringes of

(i)reducing
the separation of the double slits but keeping the width of each slit
constant,

(ii)making each
of the double slits wider but keeping the slit separation constant.

(4)

(d)You have been asked to demonstrate two-source interference with sound
waves. Describe, with the aid of a diagram which shows the approximate
distances involved, how you would do this.

3Describe an experiment you would perform, using the
same apparatus in each case, to illustrate the meaning of each of the
following terms. In each case explain what you would observe.

(i)free
vibrations

(ii) forced
vibrations

(iii) resonance

..(6)=(6)

5
(a) Explain why the apertures (or lines) of a diffraction grating for
visible light should be

(i)narrow
compared to the wavelength of visible light,

(ii) close together,

(iii) equally spaced.

(3)

(b)Sodium light of wavelength 589 nm falls normally on a diffraction
grating which has 600 lines per mm. Calculate the angle between the directions
in which the first order and second order maxima, on the same side of the
straight through position,
are observed.

(ii) the maximum velocity of the bob. State where this maximum velocity
occurs.

(4)

(b) By
referring to a simple pendulum, or otherwise, explain what is meant by

(i)free oscillations,

(ii)forced oscillations.

(2)

(c)(i)Explain what is mean by resonance. Illustrate your answer by referring to
a demonstration.

(ii)What is meant by damping? State how the amount of damping influences
resonance.

(7)=(13)

3

Graph A shows the variation of displacement with distance along the path
of a progressive transverse wave of constant amplitude at time t = 0. The wave
is travelling in the direction of the arrow. Graph B shows the same wave at time
t = 50 ms.

(a) Determine

(i)
the wavelength,

(ii)the speed of the wave,

(iii)the frequency of the vibrations producing the wave.

(3)

(b)
(i)Describe the motion of the particle whose position at t = 0 is shown by X
on the graph.

(ii)Sketch a
graph showing displacement against time for this particle, starting from time t
= 0, with scales on both axes.

Label a point P on your graph at which the speed of the particle is a
maximum.

(4)=(7)

4A
laser emitting light of wavelength 6.0 x 10‑7 m is used to illuminate two
parallel slits, giving two coherent sources. Interference fringes are to be
produced on a screen 2.0 m from the slits. The separation of the fringes
required is 5.0 mm.

(i)Calculate the distance between the centres of the two slits.

(ii)Interference takes place where light beams from the two slits overlap.
With the aid of a diagram, explain how this overlap is produced.

(iii)State and explain what two changes you would expect in the fringe system
if each of the slits was made narrower, but their separation was kept the same.

1.(a)With reference to sound waves
in air and a wave on a string, distinguish betweenlongitudinal waves and transverse waves.2

(b)Describe an experiment you could perform in a laboratory to show that
light is a transverse wave. State what you would expect to observe, and explain
your observations.

5=7

2 A
parallel beam of light from an illuminated vertical slit consists of one red
wavelength and one blue wavelength. It is incident normally on a diffraction
grating having 3.00 x 10 5 lines m‑1 placed on a
horizontal surface.

(a)The wavelength of the blue light
is 450 nm

Calculate the angle between the straight through position and the first
order maximum for this wavelength.

(b)The diffracted light is observed as the angle from the straight through
position is increased and the following lines are seen in sequence: blue, red,
blue. Then a blue line and a red line are seen to coincide.

(i) Which order
red line is the one which coincides?

(ii) Calculate the
wavelength of the red light.

(iii) Calculate the angle at
which the red and blue lines coincide.

5

(c)Diffracted light is observed at greater angles than in (b). At what other
angle,any, can a red line and a
blue line be seen to coincide?